IBN week 7

What is epigenetics?

Changes in gene expression caused by chemical modifications without changing the underlying DNA sequence.

What is DNA methylation generally associated with in your notes?

Reduced gene expression at the modified site.

What are histones?

Proteins around which DNA is wrapped.

What does histone acetylation generally do?

Makes DNA more accessible, often increasing gene expression.

Which combination is generally associated with reduced gene expression in the simplified model from your notes?

Increased DNA methylation and reduced histone acetylation.

How might early-life stress affect later mental health through epigenetic mechanisms?

It may alter gene expression influencing stress responses and vulnerability.

Which of the following is an example of a possible experience-dependent epigenetic effect?

A change in gene expression following early-life trauma.

How might epigenetic mechanisms contribute to drug addiction?

They influence gene expression in brain reward circuits following repeated drug exposure.

How could epigenetic changes be involved in adaptation to repeated food scarcity?

They alter gene expression involved in metabolism and energy regulation.

What is the main difference between a genetic mutation and an epigenetic modification?

Mutation changes DNA sequence; epigenetics changes regulation without changing sequence.

What is a key characteristic of autism spectrum disorder (ASD)?

Restricted interests, repetitive behaviors, and social communication differences.

According to your notes, ASD symptoms typically become apparent by approximately what age?

Three years.

Which statement about the causes of ASD is most accurate?

It has genetic contributions and complex etiology involving multiple influences.

What type of neurons are discussed in your notes as potentially relevant to ASD development?

Cortical interneurons.

ADHD is best described as:

Persistent patterns of inattention and/or hyperactivity-impulsivity.

Which brain region is discussed in your notes in relation to ADHD?

Prefrontal cortex.

Which neurotransmitter pathway is discussed in your notes in relation to ADHD?

Mesolimbic dopamine pathway.

Why can stimulant medications such as amphetamine help some people with ADHD?

They influence catecholamine signaling, improving attention and impulse regulation.

Which statement about ADHD is most accurate?

It has complex genetic and environmental contributions.

Which developmental disorder is commonly associated with onset in late adolescence or early adulthood?

Schizophrenia.

What does it mean to say that perception is an abstraction of sensory information?

The brain represents selected features rather than reproducing every detail.

Why might sensory systems distort incoming information?

To emphasize behaviorally meaningful features and improve useful discrimination.

Which is an example of sensory adaptation?

Becoming less aware of a constant smell after remaining in the room.

What does the law of specific nerve energies state?

Sensation depends on which pathway is activated, not solely the physical cause.

What is an adequate stimulus?

The type of energy a receptor is most sensitive to.

Which is an example of an adequate stimulus?

Photons of light for photoreceptors.

What is sensory transduction?

Converting physical or chemical energy into a neural signal.

What is a generator potential?

A graded change in membrane potential produced by sensory stimulation.

How does a sensory neuron communicate stronger stimulus intensity using rate coding?

By increasing its action potential firing rate.

What is temporal coding?

Information represented by the timing or pattern of action potentials.

What is a receptive field?

The sensory space area where a stimulus changes a neuron's firing rate.

What is rate coding?

Stimulus information represented by the frequency of action potentials.

What is the labeled-line coding strategy?

Separate afferent pathways carry particular sensory qualities.

What is across-fiber pattern coding?

Sensory qualities represented by patterns across multiple fibers with overlapping preferences.

Which example best illustrates across-fiber coding?

A taste identified by combined activity of several taste-sensitive fibers.

Why are sensory neurons often tonically active?

Baseline activity allows increases and decreases to represent changes over a wider range.

What is hierarchical processing in sensory systems?

Information is processed at multiple levels of the nervous system.

What is cortical representation?

The organization of sensory information within particular cortical areas.

What is sensory integration?

Combining information from different senses or features.

Why can sensory systems benefit from nonlinear processing?

To emphasize meaningful features like edges instead of direct proportion.

What is somatosensation?

Detection of bodily sensations like touch, pressure, temperature, and pain.

How is the location of a touch stimulus determined?

By the location of activated receptors and their neural pathways.

What is a Pacinian corpuscle especially sensitive to?

Sudden displacement and high-frequency vibration.

Why does the Pacinian corpuscle have an onion-like outer structure?

Layered capsule reduces sustained pressure response while allowing rapid changes.

What happens when a sudden mechanical stimulus deforms a Pacinian corpuscle?

Mechanically gated ion channels open, producing a graded receptor potential.

How can a Pacinian corpuscle's receptor potential lead to an action potential?

Depolarization reaching threshold in the sensory neuron generates action potentials.

Why does a Pacinian corpuscle respond less strongly to constant pressure over time?

It rapidly adapts to sustained stimulation.

What is the relationship between a generator potential and action potentials?

A generator potential is graded and can trigger action potentials if threshold is reached.

A person detects a vibrating phone in their pocket. Which receptor is particularly suited to detecting that vibration?

Pacinian corpuscle.

Which statement best connects somatosensation to cortical organization?

Sensory input is organized into maps of the body's surface in somatosensory cortex.